water or vegetable broth
tabsp oil or butter
salt & pepper to taste
greek yogurt or cream cheese
Slice leek in thin slices and sautee it with oil or butter for few minutes then add chopped lettuce, cook 5 more minutes then add water or broth.
Cook for about 20 minutes, pay attention not to let evaporate too much liquid, add some if needed.
Blend soup with a minipimer, add salt and pepper to taste (or chili if you like), serve it with a yogurt or cream cheese quenelle and chopped chives.